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Date:   Thu, 19 Jan 2023 19:46:31 -0800
From:   Jakub Kicinski <kuba@kernel.org>
To:     Jacob Keller <jacob.e.keller@intel.com>
Cc:     Saeed Mahameed <saeed@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Paolo Abeni <pabeni@redhat.com>,
        Eric Dumazet <edumazet@google.com>,
        Saeed Mahameed <saeedm@nvidia.com>, <netdev@vger.kernel.org>,
        Tariq Toukan <tariqt@nvidia.com>,
        Rahul Rameshbabu <rrameshbabu@nvidia.com>,
        Gal Pressman <gal@nvidia.com>,
        Richard Cochran <richardcochran@gmail.com>
Subject: Re: [net-next 03/15] net/mlx5: Add adjphase function to support
 hardware-only offset control
Message-ID: <20230119194631.1b9fef95@kernel.org>
In-Reply-To: <739b308c-33ec-1886-5e9d-6c5059370d15@intel.com>
References: <20230118183602.124323-1-saeed@kernel.org>
        <20230118183602.124323-4-saeed@kernel.org>
        <739b308c-33ec-1886-5e9d-6c5059370d15@intel.com>
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On Wed, 18 Jan 2023 13:33:56 -0800 Jacob Keller wrote:
> > The adjtime function supports using hardware to set the clock offset when
> > the delta was supported by the hardware. When the delta is not supported by
> > the hardware, the driver handles adjusting the clock. The newly-introduced
> > adjphase function is similar to the adjtime function, except it guarantees
> > that a provided clock offset will be used directly by the hardware to
> > adjust the PTP clock. When the range is not acceptable by the hardware, an
> > error is returned.
> 
> Makes sense. Once you've verified that the delta is within the accepted
> range you can just re-use the existing adjtime function.

Seems like we should add a "max_time_adj" to struct ptp_clock_info
and let the core call adjphase if the offset is small enough to fit.
Instead of having all drivers redirect the calls internally.